U.S. Pat. No. 4,573,318 discloses a marine propulsion system having an exhaust elbow having an intake exhaust passage extending upwardly from the engine and communicating through a bend with a discharge exhaust passage, and a water jacket having pockets around the exhaust passages for cooling the latter. A central channel extends longitudinally along the exterior of the exhaust passages to guide water there along to the end of the discharge exhaust passage to mix with exhaust thereat. The central channel has a pair of sidewalls extending longitudinally and laterally tapered away from each other at the outer end of the discharge exhaust passage to create an outward draw from the central channel to minimize break-up of longitudinally outward water flow and maintain the end tip of the discharge exhaust passage dry and prevent water ingestion and creeping back into the discharge exhaust passage due to pulsations of the engine. Dam and port structure is also provided enabling faster heating of the exhaust passage and in turn minimizing condensation within the elbow which may otherwise ingest back into the engine.